Unless you are really technically savy I would not recommend that you hack your bios on laptop. A bad bios install can render your computer useless. No reputable computer store will do this for you because it's risky.
Based on the model you provided it looks like it's a 3rd generation Intel machine, likely about 2 years old give or take. The service manual provides the product models and part # of chips that will work with the laptop but I suggest you take it to an HP authorized service location. Not sure if Bestbuy/Geek Squad does this for HP but you can ask them, or contact HP Canada to find an authorized service location.
If you want to avoid this and go a simpler route, you can get a USB wifi device that effectively replaces your internal modem and load the appropriate driver from the manufacturer and away you go with 5 Ghz support, or even AC support if you go that far. I did this before finding a good BIOS hack for my laptop and it worked well. I used an ASUS USB-N53 that cost about $ 30-40 that provided me dual band 300/300 support. Even with this unit I was able to achieve about 200 Mbits / sec wifi speed in my house on 5 Ghz band. If you want AC wifi support, the ASUS USB-AC56 should work as well and should provide even greater speed if you have a good AC wifi router.
I only went to the trouble of finding a BIOS hack because I wanted to free up my USB ports and didn't always have the space to accommodate a USB extender but it otherwise worked just fine.